In the Gulf of California, novice fishermen have to survive a psychological crit.
When they catch nets and sea bass, snappers, and silver croakers, they will find that many fish seem to have something hidden in their mouths.
Open the mouth of the fish and look at it, and a pair of small eyes stare at you.
...... Very nice and refreshing.
The insect hidden in the mouth of the fish is a crustacean parasite, scientifically named Cymothoa exigua, Chinese name is the shrunken-headed fish lice.
They are found in the southern part of the Gulf of California, in parts of the Gulf of Guayaquil and the Atlantic Ocean, and in recent years have spread to British waters.
The shrunken-headed fish lice did not accidentally burrow into the mouth of the fish.
They eat the tongue of the fish, and the dove occupies the magpie's nest, using itself as the new tongue of the fish, replacing the organs to keep the fish alive.
This is the only known way parasites replace host organs.
Although the picture is very frightening, this parasitic relationship has existed for many years, and the fish have adapted.
Like people, fish have tongues. But the fish's tongue is not well developed, with only a flattened hyoid bone with a little soft tissue on top.
Fish tongues often do very limited things, and they can only move like pistons, either sucking food into their mouths and helping to send them down, or squeezing water out of their gills.
These two things are important to fish, determining whether the fish can obtain nutrients and breathe freely.
Unfortunately, because the richest location of the tongue meat is just close to the gills, it is an easy-to-access hole, which is too attractive for parasites.
Hundreds of millions of years ago, a crustacean bug called isopoda discovered this foraging shortcut.
They pass through the gills, burrow into the mouth of the fish, and hold the tongue firmly with their slender legs, just like a surfer clings to the surfboard.
They suck the blood from the tongue and let it dry out until the soft tissues begin to atrophy, leaving only one hyoid bone.
Some will eat the tongue of the fish directly, chew it up, and drink the mucus of the fish as a drink.
Gradually, this insect evolved into what is now commonly known as the "tongue-eating lice", that is, the shrunken-headed fish lice.
They have a unique way of life.
Shortly after being born, when the shrunken-headed fish lice were only a few millimeters in size, it struggled to find a good host in the sea. The search time is usually only a few hours, after which you will die of starvation or be eaten.
Some of the shrunken-headed fish lice were lucky enough to find a fish, maybe a clownfish, maybe a snapper, and they weren't very selective in terms of species.
After burrowing into the gills, they become the new lords of the fish's mouth, and these invaders are all males, relying on the blood of the tongue and slowly growing into adult worms.
When it is time to mate, some of the male lice will become females and wait for the male to come.
If a male rings the gills (well, it's not so polite), they mate and reproduce in the fish's mouth, and the female puts the fertilized eggs into the ocean for the baby fish lice to find a new host.
If two males occupy a fish mouth together, during the mating period, one of the males will automatically become female and complete the mating.
Older fish, opening their mouths, can see more than one worm inside, and the horror effect is doubled.
(I won't put the picture here, it's really...-.) -）
Eating fish with their tongues sucking fish blood, this parasite looks really disgusting.
But the scientists found that the parasitic fish did not suffer much in terms of health.
Seeing this, did you think of barnacles?
When it comes to food, we can always talk about most of the day, and delicious seafood is more frequently in the camera.
However, there is a strange and ugly seafood that few people know, that is, it is called "the delicacy from hell" - barnacles.
If you only talk about looks, I really don't dare to think about the mentality of the first person to eat it, but its deliciousness can conquer every diner.
In terms of taste, they are not at all tender like shellfish and snails.
But looking at its iconic calcareous shell, is it a "traitor" among mollusks?
However, it is the wrong barnacles, they are actually close relatives with shrimp and crabs, and even scientists have classified them in the wrong category.
However, with the deepening of research, scientists have discovered the true identity of barnacles.
Their characteristics are not just delicious.
As early as 1861, Darwin became interested in this creature that made his home.
In the early days of his research, he spent 8 years classifying them and other related work.
The vines, represented by barnacles, were the first biological taxa that Darwin studied using modern systems biology perspectives.
Barnacles can be described as the early cornerstone of biological evolution, known in history as "eight-year barnacles".
Before hatching from the egg mass, they also go through three stages: arthropods, adeno-larvae, and adults*.
When they are still larvae, they are closer to ordinary shrimp and crabs.
Therefore, they are also crustaceans and belong to the crustacean subphylum.
*Note: Crustacean hatched larvae are not segmented, have three pairs of auxiliary limbs, a middle eye, and live as plankton; adenite larvae are the planktonic larval stage of cranbercus following the arthropods, because of their appearance similar to those of shellfish, hence the name.
Before growing into an adult, barnacles are actually "cute" on the seabed.
In the first stage of the knotless larvae, there are also faces and eyes, and the glowing little eyes fully show the curiosity of an ignorant baby about this marine world.
At this time, the body size is about 1 mm, and it can paddle and flutter with the waves.
Barnacles in this period only care about eating and drinking, and growing up is the most important.
After eating and drinking enough, they will metamorphose into glandular larvae.
Adenite larvae are a special form of larvae that do not need to eat, but are tasked with finding a place to live.
They are pulled by the current of water or moved by small tentacles.
When they come to a good substrate, they can choose:
cling? (Yes/No)
The lower few are the tentacles
If they choose to attach, the next probe is performed.
They walk on the surface of the substrate with regular "steps" of small tentacles.
On this basis, they confirm the suitability of all aspects of the substrate.
If they feel fitted, the barnacles secrete glue that reaches the chassis through the duct and comes into contact with the substrate to achieve attachment.
Of course, if you feel inappropriate and not yet perverted, you can continue to look for the right substrate.
After all, it is a place to live for a lifetime, and barnacles are very particular about this.
Biologist Wethey believes that the speed of water flow is the main consideration for barnacles to choose a residence.
After much experimentation, he found that only the water flow rate/tilt on the surface of the substrate was critical:
Above 50/s, the attachment probability is higher.
Once it exceeds 100/s, the adhesion rate will decrease again.
If 400/s is reached, no larvae will be able to attach to it.
However, other studies argue that the substrate environment is more important.
Barnacles, for example, will be more inclined to choose a rougher substrate.
Small antennae help them distinguish between terrain conditions, and nerve impulses caused by irregular substrates induce them to attach and metamorphose.
If the light attached to the substrate is dim, the barnacles will be happier.
And light can also induce them to attach, orange and green will attract them more, while yellow is basically not considered.
Secret Fear Warning
Barnacles are a fight with people who choose a lot to buy a house.
Whether it is the type and color of the substrate, or the light, temperature, salinity, humidity will have an impact on its choice, it can be said that it is very picky.
If the substrate can give some other gimmick, barnacles will buy it too.
For example, some substrate surfaces are rich in arthropodin, which can attract a large number of barnacles.
Many animals have similar proteins in their bodies, which are released into seawater by animal tissues and absorbed by the surface of the substrate.
However, the study has not yet been able to determine what role these proteins play in the process of larval attachment to metamorphosis.
Perhaps it is the charm of water and protein, and live animals such as whales will also become their gathering places.
Being able to attach more firmly to living bodies, they will embed their calcareous shells into their bodies.
Barnacles prefer to live in groups, and large barnacles are embedded in the surface of the whale's body, giving the whale a little more cute appearance.
Of course, different kinds of barnacles pursue different lives.
Some barnacles prefer to be attached to the vicinity of the same kind, which is convenient for reproduction;
Some barnacles are more focused on the "way of eating", preferring to settle near specific food sources;
Others have requirements for neighbors, ryūsuke larvae, anthemites will grab food, and bone snails like to eat barnacles, naturally can not live near them;